RESUMO
To evaluate a possible involvement of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism in susceptibility to Parkinson's disease (PD), we performed a meta-analysis of all studies on the topic published from 2002 to 2014. This article reviews and compares the data from two previous meta-analyses, including two studies not previously considered. We selected studies referring to a genetic comparison between PD patients and healthy controls, so 15 studies involving 3754 cases and 4026 controls were included in our meta-analysis. We found no association between the Val66Met polymorphism and the risk of developing PD in our overall analysis. The ethnicity-specific meta-analysis produced no significant association either. Our data do not support a major role for the BDNF Val66Met polymorphism in the pathogenesis of PD.